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/*
* Creates audit record for dropped/accepted packets
*
* (C) 2010-2011 Thomas Graf <tgraf@redhat.com>
* (C) 2010-2011 Red Hat, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/audit.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/if_arp.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_AUDIT.h>
#include <linux/netfilter_bridge/ebtables.h>
#include <net/ipv6.h>
#include <net/ip.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Thomas Graf <tgraf@redhat.com>");
MODULE_DESCRIPTION("Xtables: creates audit records for dropped/accepted packets");
MODULE_ALIAS("ipt_AUDIT");
MODULE_ALIAS("ip6t_AUDIT");
MODULE_ALIAS("ebt_AUDIT");
MODULE_ALIAS("arpt_AUDIT");
static void audit_proto(struct audit_buffer *ab, struct sk_buff *skb,
unsigned int proto, unsigned int offset)
{
switch (proto) {
case IPPROTO_TCP:
case IPPROTO_UDP:
case IPPROTO_UDPLITE: {
const __be16 *pptr;
__be16 _ports[2];
pptr = skb_header_pointer(skb, offset, sizeof(_ports), _ports);
if (pptr == NULL) {
audit_log_format(ab, " truncated=1");
return;
}
audit_log_format(ab, " sport=%hu dport=%hu",
ntohs(pptr[0]), ntohs(pptr[1]));
}
break;
case IPPROTO_ICMP:
case IPPROTO_ICMPV6: {
const u8 *iptr;
u8 _ih[2];
iptr = skb_header_pointer(skb, offset, sizeof(_ih), &_ih);
if (iptr == NULL) {
audit_log_format(ab, " truncated=1");
return;
}
audit_log_format(ab, " icmptype=%hhu icmpcode=%hhu",
iptr[0], iptr[1]);
}
break;
}
}
static void audit_ip4(struct audit_buffer *ab, struct sk_buff *skb)
{
struct iphdr _iph;
const struct iphdr *ih;
ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
if (!ih) {
audit_log_format(ab, " truncated=1");
return;
}
audit_log_format(ab, " saddr=%pI4 daddr=%pI4 ipid=%hu proto=%hhu",
&ih->saddr, &ih->daddr, ntohs(ih->id), ih->protocol);
if (ntohs(ih->frag_off) & IP_OFFSET) {
audit_log_format(ab, " frag=1");
return;
}
audit_proto(ab, skb, ih->protocol, ih->ihl * 4);
}
static void audit_ip6(struct audit_buffer *ab, struct sk_buff *skb)
{
struct ipv6hdr _ip6h;
const struct ipv6hdr *ih;
u8 nexthdr;
int offset;
ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_ip6h), &_ip6h);
if (!ih) {
audit_log_format(ab, " truncated=1");
return;
}
nexthdr = ih->nexthdr;
offset = ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(_ip6h),
&nexthdr);
audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu",
&ih->saddr, &ih->daddr, nexthdr);
if (offset)
audit_proto(ab, skb, nexthdr, offset);
}
static unsigned int
audit_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct xt_audit_info *info = par->targinfo;
struct audit_buffer *ab;
ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT);
if (ab == NULL)
goto errout;
audit_log_format(ab, "action=%hhu hook=%u len=%u inif=%s outif=%s",
info->type, par->hooknum, skb->len,
par->in ? par->in->name : "?",
par->out ? par->out->name : "?");
if (skb->mark)
audit_log_format(ab, " mark=%#x", skb->mark);
if (skb->dev && skb->dev->type == ARPHRD_ETHER) {
audit_log_format(ab, " smac=%pM dmac=%pM macproto=0x%04x",
eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
ntohs(eth_hdr(skb)->h_proto));
if (par->family == NFPROTO_BRIDGE) {
switch (eth_hdr(skb)->h_proto) {
case __constant_htons(ETH_P_IP):
audit_ip4(ab, skb);
break;
case __constant_htons(ETH_P_IPV6):
audit_ip6(ab, skb);
break;
}
}
}
switch (par->family) {
case NFPROTO_IPV4:
audit_ip4(ab, skb);
break;
case NFPROTO_IPV6:
audit_ip6(ab, skb);
break;
}
audit_log_end(ab);
errout:
return XT_CONTINUE;
}
static unsigned int
audit_tg_ebt(struct sk_buff *skb, const struct xt_action_param *par)
{
audit_tg(skb, par);
return EBT_CONTINUE;
}
static int audit_tg_check(const struct xt_tgchk_param *par)
{
const struct xt_audit_info *info = par->targinfo;
if (info->type > XT_AUDIT_TYPE_MAX) {
pr_info("Audit type out of range (valid range: 0..%hhu)\n",
XT_AUDIT_TYPE_MAX);
return -ERANGE;
}
return 0;
}
static struct xt_target audit_tg_reg[] __read_mostly = {
{
.name = "AUDIT",
.family = NFPROTO_UNSPEC,
.target = audit_tg,
.targetsize = sizeof(struct xt_audit_info),
.checkentry = audit_tg_check,
.me = THIS_MODULE,
},
{
.name = "AUDIT",
.family = NFPROTO_BRIDGE,
.target = audit_tg_ebt,
.targetsize = sizeof(struct xt_audit_info),
.checkentry = audit_tg_check,
.me = THIS_MODULE,
},
};
static int __init audit_tg_init(void)
{
return xt_register_targets(audit_tg_reg, ARRAY_SIZE(audit_tg_reg));
}
static void __exit audit_tg_exit(void)
{
xt_unregister_targets(audit_tg_reg, ARRAY_SIZE(audit_tg_reg));
}
module_init(audit_tg_init);
module_exit(audit_tg_exit);
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